Dr. Charles W. Niessen, 82, of Heald Road in Carlisle, died on April 22 in Concord, MA following a period of declining health. Dr. Niessen was born on March 7, 1940 in Bethlehem, PA, the only child of the late William "Ted" and Ruth (Anderson) Niessen. Dr. Niessen, or "Pete" as he was known to childhood friends, was raised in St Paul, MN, where he graduated high school from Minnehaha Academy in 1958. He attended the Massachusetts Institute of Technology, where he was active in both the Tech Model Railroad Club and early efforts to develop machine learning algorithms. He graduated with his SB and ScD in Electrical Engineering in 1962 and 1965, respectively. After graduation, Chuck moved to Carlisle MA in 1967, and spent his entire career working at MIT Lincoln Laboratory in a variety of areas including foundational work on long range radio communications; signal processing algorithms; optical sensing and discrimination; and satellite communications architectures for NASA and other users. He found great joy and pride in his continuing affiliation with the MIT community. His hobbies included photography, traveling, golf, skiing, and endless DIY projects on his house, his vehicles, and in his home electronics laboratory. He was also an active member of Trinity Episcopal Church in Concord for many years, including over 20 years leading their community of volunteer ushers. He is survived by his four children, Dr. Karen Rusch and her husband Dr. Jerry Rusch, of Mitchell, IN; Peter Niessen and his wife Lauren Margulies, of Carlisle, MA; Dr. Christopher Niessen and his wife Genevieve Niessen, of Medford, MA; and Robert Niessen, and his partner Jennifer Smith, of Novato, CA, as well as his three grandchildren, Sophia, Charles, and Leah. Chuck's Memorial Service will be held at Trinity Episcopal Church, Concord, MA, at 10 am on Saturday, April 30th. For those than are unable to attend in person please  click to watch the church's livestream  . In lieu of flowers, donations can be made to  Trinity Episcopal Church  , 81 Elm Street, Concord MA, 01742, or the  MIT Tech Model Railroad Club  . Arrangements are under the care of Dee Funeral Home & Cremation Service of Concord.